World's Biggest Pagoda Structural Damage Questions

Elaine Meinel Supkis

I have rebuilt the foundations of more than one building in my own time including a spectacular saving of a Victorian 'flying tower' that was on the verge of collapse. So this Xinhua story intersts me a great deal. I wish I could see the plans suggested for saving the world's biggest historic pagoda!

YINGXIAN, Shanxi, Sept. 3 (Xinhua) -- Chinese scientists have been seeking ways to prolong the life of a 950-year-old wooden pagoda in northern Shanxi Province by another millennium, but they are still baffled over how to do it.

The Sakyamuni Pagoda with unique architectural, religious and historical values is located at the Fogong (Buddha's Palace) Temple in Shanxi's Yingxian County, 380 km southwest of Beijing. It was built in 1056 during the Liao Dynasty, which ruled North China from 916 to 1125. China will celebrate the 950th anniversary of the pagoda on Sept. 5.

Experts have proposed three options: dismantle it and rebuild it with the original timber parts and technology; elevate the top three stories to fix the two bottom stories and then place the top three back to position; reinforce the damaged and twisted parts with steel structures, said Fu Xi'nian, a research fellow with the Institute of Architectural History under the Beijing-based China Architecture Design and Research Group.

No building lasts long if it has a bad foundation. I often beg people designing or building a new home to please spend extra money on the foundation putting in drainage pipes, putting in the right subsoil fill, coating the walls not only with tar but sticking waterproof barriers onto the tar, sealing the cement. Using lots and lots and then even more rebars, etc. Of course, this takes away money that can be used to put in frills and follies that everyone can admire!

So this advice often goes into the ether, in one ear and out the other.

This is beyond stupid. I have fixed houses that were less than 20 years old! Water and insects, both following Mother Nature's laws to go where they may and do what they want, can rapidly eat away the foundations or wood supports of a building!

Any building more than 300 years old that is still standing is a testiment to the builder's care in preparing the foundation and following generations keeping the roof in good repair. The Acropolis in Greece wasn't destroyed because of the foundation, for example, for it is set on a massive rock outcropping that is very solid. It could stand for thousands of years more except for the destruction caused by human beings. The roof was allowed to fail, then the Ottoman military stored munitions there and it blew up. Incredible! Gah!

Of course, roaring wars and the military are probably the number one destroyer of buildings, bar none except volcanoes and tsunamis or meteroite strikes.

Both plans called for huge steel structures -- Southeast University's needs 1,300 tons and Taiyuan University of Technology's needs 4,000 tons -- to be set up around the pagoda, which will inevitably cause "severe disturbances" to the pagoda and produce "unpredictable consequences," Ma said.

In addition, the plans would take as much as 90 million yuan (11.25 million U.S. dollars), and about six to 10 years to repair the pagoda, he said. "That is really terrifying."

I always tell people, when a problem with the foundation is too big, it is nearly as expensive to save a building as it is to replace it. With a historic structure with the history of this building, saving it is very important. In Japan, they commonly tear down old temples and replace the interior structure with new timbers and then reassemble the ornate woodwork that sheaths the main frame. The need to replace the weightbearing timbers of the Chinese pagoda is of highest importance because once a structure's stress load has disarranged the connective fibers within a piece of wood, it is permenantly weakened.

Wood can fail very suddenly. I was called to save a 'flying tower' in New Jersey years ago. Flying towers were very popular in Victorian times but nearly all of them have since collapsed because the way they were built was very serioiusly flawed from a technical point of view. In this case, this being one of only a few dozen houses with flying towers of any considerable size left on the East Coast, I decided to see what the internal structure was. The tower was leaning off kilter by 6 degrees from vertical which wasn't so bad except I had this fear it might be worse than it looked. The entire structure had a very bad foundation of fancy brickwork which was rapidly losing its integrity due to the loss of cement between the bricks, a common problem with many old Victorian buildings. I decided to remove some of the wood ceiling of the porch near where the tower attached to the building.

The minute I half-pried the first board, there was this onimous 'creak, creak, creak' sound as if a giant was walking over the floor above my head. I dropped the crowbar and hammer and ran.

It didn't fall. BARELY. We had to assume the thing was going to collapse entirely and I had to first build an elaborate scaffolding around the tower and under the tower and then begin demolition of the ceiling. The only thing attaching the tower to the main building was one floor joist! The other 12 joists were detached and three of them were crushed laterally by a century of weight of the tower which was three stories tall.

I didn't restore the original structure because the original builders, following the favored techniques of the day, built a really crummy design, namely, it was build to fail. Instead of curving the outside sill, I installed a sub structure of steel i-beams that ran around the perimeter in a heptagon shape. Instead of three pillars, I used four to hold it up. Within each pillar which reproduced the original, I inserted steel posts. The original foundation was only a foot deep. I sank holes four feet deep and put in much wider footings, 2'x2'. Instead of a wood brace holding up all the floor joists, I used long bolts to bolt a steel L brace to the main beams of the main house and then bolted L braces onto each floor joist of the tower and bolted those to the brace attached to the house.

China Culture: The pagoda was built on a stone platform four meters high. Around the upper edge and at the corners of the platform there are sculptures of crawling lions whose simple and unsophisticated style belongs to the Liao Dynasty. The exterior of the pagoda is divided into five levels, but there are actually nine levels in the interior, including four built-in storeys. The ground floor has a ring of side corridors and eaves, so it has a total six-layer eaves, the lower two formed into multiple eaves. Under each of the succeeding four layers there is a further dark layer, so the structure actually has nine layers. The exterior of the dark layer is called "level seating" which is a ring of corridors with balustrades around the pagoda itself. Each floor consists of inner and outer rings of pillars. The pillars on each floor slant slightly inward, the plane size diminishing floor by floor, although the figure remains stable. The windowless outer walls on the ground floor, the added enclosing corridors and eaves all strengthen the sense of stability.

The steeple of the pagoda is ten meters high; the whole pagoda, 67.31 meters high. The diameter of the octagonal first storey is 30.27 meters, the longest among ancient pagodas.

In Europe, there are still astonishing examples of such wood work still standing. When I lived there, I would ask people living in ancient buildings to let me into the attic to see the roof's structure. It gave me many satisfying hours, sketching these places. Since most castles were blown apart by wars, one could see inside the walls, for example. I have never been to Asia. I would love to see how they solved the many problems of buidling heavy, durable structures. Just like I see all over the place, when people in America build walls to hold back the mighty earth on hillsides and slopes, they nearly always build vertically instead of sloping back into the mass of earth pushing outwards! This is really stupid. Invariably, no matter what materials are used, the wall will be pushed from the top outwards until it topples over. So why do this?

Comments

Elaine, when m financial position improves I shall call upon you to consult in the restoration and modernization of a great old Victorian house. I used to live in a three storey place with lots of the original woodwork and two original fireplaces and glorious mantels. I adore old houses, but I equally adore light.

My current project is at a standstill.

This is very interesting - and I'd love to hear how you decided to make a living restoring houses. I don't know too many female contractors. My sister should have been one - also her daughter-in-law.

I was never a contractor. I taught people how to build things. When one is a contractor, one has to have insurance and pay workman's comp etc which is why everyone who is hired to work today are illegals who are off the books and totally hidden.

Sigh. It is all such a mess.

Anyway, finding someone who can do Victorians is a very dangerous thing since most people sort of muck along. Victorians are quite specific buildings and people who know what they are doing are not so easily found.